1. Field of the Invention
The present invention relates to a support roller of a crawler type traveling apparatus.
2. Description of the Prior Art
A crawler type traveling apparatus (a chassis apparatus) has been conventionally structured, as shown in FIG. 6, such that a track frame 51, an idler 52 and a sprocket 53 are arranged approximately rectilinearly, support rollers 54 and 54 and track wheels 55, . . . are rotatably provided in the track frame 51, and a crawler belt 56 is wound around the idler 52, the support roller 54, the sprocket 53 and the track wheel 55. Further, the crawler belt 56 is provided with a plurality of crawler belt links 57, . . . , connection shafts 61, . . . pivotally connecting a plurality of links 57 in an endless manner, shoe plates 60, . . . (refer to FIG. 6) mounted to the links 57, . . . , and the like.
Further, the support roller 54 is provided with a shaft 65, and a roller 67 which is rotatably supported to the shaft 65 via bearings 66 and 66, for example, as shown in FIG. 7. The support roller is supported to the track frame 51 in a cantilever manner, and is structured such that one end portion of the shaft 65 is protruded from the roller 67, and a protruding portion 65a is supported to a mounting bracket 68 which is stood from the track frame 51. Further, a pair of collar portions 70 and 70 are provided in an outer peripheral surface of the roller 67. As shown in FIG. 8, when supporting the crawler belt 56 by the support roller, each of the links 57, . . . are brought into contact with an outer peripheral surface 67a of the roller 67 in an outer side (an outer side in a roller axial direction) of each of the collar portions 70 and 70.
Further, there is a structure in which the crawler belt is supported by a pair of rollers (for example, refer to patent document 1). In the structure described in the patent document 1, as shown in FIG. 8, a pair of mounting brackets 72 and 72 are stood from a track frame 73, and one end portions of shafts 74 and 74 are supported to the mounting brackets 72 and 72. Further, rollers 75 and 75 are rotatably supported to a side of inner end portions of the shafts 74 and 74 protruding from the mounting brackets 72 and 72, thereby supporting a crawler belt 76.
Patent Document 1
Japanese Utility Model Publication No. 1-25754 (pages 1 and 2 and FIG. 1)
By the way, in the structure in FIG. 7 mentioned above, in the case that the soil or the like comes down onto the track frame 51 from the crawler band 56, an open space is provided in an opposite side to the mounting bracket 68 because the support roller 54 is supported in a cantilever manner, so that the soil or the like comes down from the open space. However, the soil or the like is accumulated between the track frame 51 and the mounting bracket 68, in a side of the mounting bracket 68. Accordingly, there is a risk that a stable rotation can not be achieved due to an increase of a rotational resistance caused by a friction with respect to the accumulated soil or the like.
Further, in the structure shown in FIG. 8 mentioned above, there is a risk that the soil or the like is accumulated between the rollers 75 and 75 and the track frame 73, and the like. Accordingly, in the same manner as that shown in FIG. 7 mentioned above, there is a risk that a stable rotation can not be achieved due to an increase of a rotational resistance caused by the friction with respect to the soil or the like. Therefore, in the support roller shown in FIGS. 7 and 8 mentioned above, an outer shape of the support roller is frequently worn by the soil or the like accumulated near the support roller. Further, in the crawler band guided by the support roller, a wheel tread of the link is frequently worn. Further, since these elements are supported in the cantilever manner, comparatively great shear force and bending moment are applied to the shaft and the mounting bracket, and the shaft tends to be damaged.